Connecting device and manipulating tool

ABSTRACT

Various forms of connecting devices are disclosed including one form that fastens a panel to another panel or to a stud, also adaptable to use as a door latch, another form which is united to a cable or a wire to be secured in an internally shouldered hole, another form enabling a rod to be secured in a mounting hole, and still another form that can serve as a pressure-tight plug or, in a modification, as a fitting, for mounting in the wall of a pressure vessel. The connecting device includes a body to enter a hole in the apparatus with a flange of the body bearing against the apparatus adjacent the hole, and a claw unit having claws or fingers arranged with their abutment ends biased generally toward the flange, to be thrust endwise against an abutment surface of the apparatus in or adjacent to the hole, and a spring for biasing the flange and the abutment ends of the claws toward each other to grip the apparatus; and a cowl or shroud fixed to the body for confining the spring and for constricting the claws against lateral shift. Each connecting device is a single unit which can be quickly and very securely applied to the receiving hole but which can be readily removed, and which requires access to only one surface of the apparatus for manipulation. The connecting device has a toolreceiving recess and a shoulder in the recess; and an applying and removing tool has working parts that enter the recess, including one tool part which is forced by a second tool part to interlock with the shoulder in the recess; and then the second tool part drives the connecting device into its released configuration.

[45] Dec. 31, 1974 CONNECTING DEVICE AND Primary Examiner-Roy D. Frazier Assistant ExaminerLawrence J. Staab MANIPULATING TOOL [76] Inventor: George Hamlin Leonard, 327

Hollow Tree Ridge Rd. Conn. 06820 May 25, 1972 Appl. No.: 256,782

Darien,

[22] Filed: Various forms of connecting devices are disclosed ineluding one form that fastens a panel to another panel or to a stud, also adaptable to use as a door latch, an-

other form which is united to a cable or a wire to be secured in an internally shouldered hole, another form enabling a rod to be secured in a mounting hole, and still another form that can serve as a pressure-tight H 45 3 O 0 w 3 0 3 3 1 R M M 9 M 3 213 7 EA 20 m "B 8 W7 3 9 2 moo 6 2 W 2 5 U l. 2 5 I plug or, in a modification, as a fitting, for mounting in [51] Int. Cl. IIOlr 11/00, A44b 17/00, B67b 7/00 [58] Field of searchuwm 24/73 PF, 73 PM, 73 PP the wall of a pressure vessel. The connecting device 24/73 SB 1 10, 208 R, 211 R, 219; 85/5 R, includes a body to enter a hole in the apparatus with a 80 81; 287/1895; 292/19 20; 339/75 A, flange of the body bearing against the apparatus adja- 17 M, 214, 215, 252 253, 255; 29/203 H, cent the hole, and a claw unit having claws or fingers 203 HM, 278 267, 268; 81/425 426, 3057 arranged with their abutment ends biased generally 3344.37 3'4, 341, 342 3.48 14913], toward the flange, to be thrust endwise against an abutment surface of the apparatus in or adjacent to the hole, and a spring for biasing the flange and the abutment ends of the claws toward each other to grip [56] References Cited the apparatus; and a cowl or shroud fixed to the body UNITED STATES PATENTS for confining the spring and for constricting the claws BQ a EB b mm m n m hme n .m a pfi a S%m wS.whI HC flh H .Ir a WOT hv a C W t a m m p kd .1 t h MkD-W m r nm WhD.. 6. a w nmk c le ewO nh e m ot t a. o.me.m O t h e a .85 t 1 df 3 0 d onl et e ne UU n 0 a o c o 0 an D- h ate anrm nS g d a amn n d ro lln w yucd g ef n C I VI n md c .wcwm mmde I 6 in nc d rOTee en lm y Cr wwrn S n bw m dae o l. ne n mc m cvaonn ma n w mm c mw m mmm h w wrm m t my uwclt e U S W dd g n W e .I CC enlaecu n we mmm wnmm mflo aEqbamtaefsdc WWRXWWQWUARXRXH Hum n m n o m 4 19R9R l l 2 /12 2 /1 1/ S M2 29 N u I 2/./2 "a p O 2 4 4 2 2 u I m2 T .mn I l "um Dr num n U a n u n n P mmw wmmmm mmmmMm m m m m m J 1 arm 5 M %.mkm r ww wmsflm S ll n 8 wmm m m ma mwww M CPLWGFKGMJSSH E T 5 735 6 349 A 000 4455666667 P 00999999999999 HHHHHHHHHHHHH N l l I E 5O 573 579253 R 96 094997278 0 .J .33 .D F 4977395 06598 l74l74500992 J3 v u 1 2222223333 ll/l952 Norway........... 24/211 R 27 Claims, 20 Drawing Figures PATENTED 1 3,858,164

PAIENTEH 3,858,164

SHEET 3 OF 3 FIGJB CONNECTING DEVICE AND MANIPULATING TOOL This invention relates to connecting devices of vari ous forms, useful for mechanical fastening, for both mechanical and electrical connection, and for pressure-tight securement in a hole in a wall as a plug or a fitting.

BACKGROUND OF THE INVENTION There are innumerable known fasteners and connectors, each with its own limitations. Some mechanical fasteners to be applied to a hole in an external wall surface require assembling of separate parts, or they in volve parts that separate and may be lost when the fastener is being removed. Some fasteners for use on apparatus having only one accessible surface are secure but permanent, and they cannot be removed and applied, repeatedly. Some removable fasteners can be securely mounted, but require a great deal of careful time-consuming effort.

Still further, there are fasteners that are inherently bulky (for a given strength), some that require precise mounting or mounting holes of special shape, and some that are useful (as to any one size of unit) only for mounting panels with a narrow range of panelthicknesses. There are fasteners that inherently involve a prominent or disfiguring external projection; some that are delicate, and some that are costly. There are connecting devices that can readily be released by anyone without special knowledge or tools, and such devices are vulnerable to operation without authorization, creating security risks. It would not be practical to describe the many prior art fasteners or connectors (only a relatively small number of which are actually known to the present inventor), and to contrast those devices, individually, with the novel connecting devices.

SUMMARY OF THE INVENTION In its various forms described below, the novel unitary connecting devices avoid the foregoing and other limitations of prior art fasteners and connectors. The illustrative embodiments shown in the drawings all include a flanged body which is ideally formed as a figure of revolution having a lateral guide surface. A claw unit has a series of claws that slide along the lateral guide surface and they diverge toward the flange, so that the claws can be retracted axially and radially and the connecting device can then be inserted into a mounting hole, and then the claws can advance divergently toward the body flange to grip themounting structure around the hole that receives the connecting device, gripping the material between the claw ends and the flange. A shroud fixed to the flanged body constricts the claws against spreading laterally under stress, and insures the inward retraction of the claws when they are retracted lengthwise; and a compression spring confined between the shroud and the claw unit biases the claw ends and the body flange toward each other to grip the mounting structure.

The claw unit in some cases includes a cup portion whose bottom is flat and, in use, flush or approximately flush with the outside face of the flange, thereby affording an attractive external appearance. The fastener can be mounted captive to a door and used as a door latch which is relatively secure against unauthorized release.

the connecting device, for entering a recess in the con necting device, becoming securely interlocked with it, and operable to drive the claws into their retracted configuration against the force of the biasing spring of the connecting device. The connecting device carried by the tool is then inserted into a receiving hole in the mounting structure, and becomes securely mounted when released by the tool. The connecting device is just as easily removed, by insertion and interlocking action of the tool, followed by release operation of the claws to free the connecting device for removal.

In the preferred construction, the claw unit involves claws that extend outward and downward from the edge of a cup; and the biasing spring is a compression coil spring that is confined with pre-compression between the bottom of the cup and the shroud fixed to the body of the connecting device, so that the unit can have a relatively small dimension in the direction ofinsertion and removal.

As a mechanical fastener, the connecting device can be made remarkably small yet strong. It can present a flush exterior at the external mounting surface. No access to the rear of the mounting structure is needed for applying and removing the connecting device. When used to secure two panels together, a connecting device of a given size can accommodate relatively wide tolerances of the panel thicknesses and a range of variation in location of the receiving holes, and no special preparation of the panels is needed other than to make holes of the right size and in the right locations, again without requiring precision. In its preferred form, the 'end of the connecting device that first enters the receiving hole is selfcentering because of a conical end formation.

The fastening device can be secured to one panel or a door to act as a latch, and then it serves as a security latch since only authorized personnel will ordinarily have the specialized tool needed to release the latch. In its preferred form, the rear portion of the latch is tapered and can enter a receiving hole even when the door is small and is swung on hinges only inches away from the latch.

The connecting device can be used for making electrical connections between two parts held together thereby. In a modification, a wire can be attached to the claw unit, to project forward; and then the claw which may be of high-conductivity spring stock such as phosphor bronze provides a direct current-path from the wire to the tips of the claw which engage the receptacle contact surface. The biasing spring of the connector holds the claws in firm contact with the receptacle, but the spring is not relied on to resist pull that may be applied to the wire. Quick, secure and vibration-proof mounting are inherent, and yet the connector is quickly and easily released.

Inclusion of O-rings renders the basic connecting device very effective foruse in pneumatic and hydraulic applications. The claw unit can have a cup with a closed bottom, in which case the device becomes a plug to close a port in the wall of a tank or manifold. A fitting can be united to the cup of the claw unit, to serve as a pressure connector for a guage, a valve, a connecting tube, or the like. The connecting device is characteristically applied quickly and easily yet securely, and it is removable quickly and easily, as may be required.

When there is a hole in the bottom of the cup and a hole in the cowl, there is a passage through the device, which is used in the connecting device that serves as a pressure fitting. The same two holes are useful for providing firm mounting support for a rod. Moreover, where the rod is an auto radio aerial, the connecting device provides secure mechanical and electrical connection to the receptacle; and removal for replacement is a quick and easy operation.

The tool or separable handle for the connecting device involves a part that can enter a recess in the body of the device and engage a shoulder in it; and a second tool part forces the first part. to interlock with the shoulder, uniting the tool to the connecting device. Further motion of the second tool part applies forces to the body and the claw unit to overcome the spring bias and retract the claws. That operation is the same for both insertion and removal of the connecting device.

The nature of the invention in its various aspects will be more fully appreciated, together with further novel features and advantages, from the following detailed description of several illustrative embodiments which are shown in the drawings.

In the drawings: a

FIG. 1 is the top plan view ofa connecting device embodying features of the invention;

FIG. 2 is a vertical cross-section of the connecting device as viewed from the cross-section line 2-2 in FIG. 1, including panels that are fastened together by the connecting device, shown in phantom;

FIG. 3 is a bottom plan view of the connecting device of FIGS. 1 and 2;

FIGS. 4 and 5 are perspective views of two components of the connecting device of FIGS. 1 and 2;

FIG. 6 is a lateral view of the connecting device of FIGS. 1-3 partly in cross-section, showing the relative positions of its parts as they appear when separating force is developed between the panels fastened together by the connecting device, the panels appearing in phantom;

FIG. 7 is a lateral view, partly in cross-section, of the connecting device of FIGS. l-3 together with the cooperating parts of a separable insertion-and-removal handle or tool aligned with the fastening device;

FIG. 8 is a modification of the manipulator of FIG.

FIGS. l-8 are greatly enlarged.

FIG. 9 is a lateral view of a separable insertion-andremoval handle, for the connecting device of FIGS. l-3, including the parts of FIG. 7;

FIG. 10 is a lateral view of parts of the separable tool or handle of FIG. 9, including pins shown in crosssection;

FIG. II is a rear view of the separable tool or handle for the device of FIGS. I-3, as seen from below FIG.

FIG. 12 is the end view of the separable handle as seen from the left of FIG. 9;

FIG. 13 is an enlarged lateral view of the connecting device of FIGS. l-3 securing a panel to a hollow stud, the panel and part of the stud being shown in crosssection;

FIG. 14 is an enlarged lateral view of a connecting device internally like that of FIGS. I3, externally modified and shown captive to a door panel and securing the door panel to a'wall panel of a cabinet, the door and the wall panel being shown in phantom;

FIG. 15 is a view, partly in cross-section, illustrating a further application of connecting devices like that of FIG. 1;

FIG. 16 is an enlarged lateral view, partly in crosssection, of a receptacle and an electrical connector therein, being the same as the connecting device of FIGS. l-3 except for the addition of a cable secured to the bottom thereof;

FIG. 17 is a modification of the connecting device of FIGS. l-3 adapted to serve as a plug or as a connector for fluid under pressure, this figure being an enlarged cross-section like that in FIG. 2;

FIG. 18 is the enlarged end view of a tool like that in FIGS. 7-12, modified to cooperate with the connector of FIG. 16;

FIG. 19 is an enlarged lateral view, partly in crosssection, of a further modification of the connecting device of FIGS. 1-3, incorporating a rod supported thereby, the connecting device of FIG. 19 being operated upon by a tool (shown in phantom) of the form in FIG. 18; and

FIG. 20 is a lateral view of the connector of FIG. 16, in use as a test connector for printed-circuit boards shown in cross-section.

Referring now to the drawings, FIGS. l-6 represent a fastening device illustrated as connecting two panels A and B together. The fastener includes four components parts: a body 10 (FIG. 4), a cowl or shroud 12 which is generally bell-shaped in the example, a claw unit 14 (FIG. 5), and a compression coil spring 16. All four of these components are of metal.

Body 10 (FIG. 4) is formed basically as a figure of revolution. At the bottom of body 10 as represented in FIGS. 2 and 4, there is a flange 18 that has conical taper matching the chamfered hole in panel B so that the external face 20 of body 10 is flush with the exter nal surface of panel B. Cylindrical portion 24 of body 10 extends through approximately aligned holes in panels A and B. Above portion 24 at opposite sides of body 10 are two guide surfaces 26 terminating at upper edges 26a. Body 10 also includes a pair of posts 28 that are separated from guide surfaces 26 by parallel slots 30. Posts 28 have outward projecting feet 32 and adjoining shoulders 32a.

Claw unit 14, (FIG. 5) is formed of moderately springy sheet metal, including a cylindrical wall portion 34 and a closed bottom 36; and a series of claws 38 depend from the upper end of cylindrical wall portion 34, remote from bottom 36. There are two groups of claws 38 that are separated by gaps 40. Claws 38 extend over upper edges 26a of the guide surface 26. The claws 38 and guide surfaces 26 are curved alike as an arc of a circle. The radius r of the arc (FIG. 2) extends perpendicular to the central axis of body 10 approximately at the level of upper edge 26a, in an example. The claws 38 are curved along their lengths as arcs of radius r, being an arc of 30 in an example where the diameter of portion 24 is V; inch. Any cross-section of a claw 38 transverse to its length is a rectangle whose width represents the thickness of the claw.

Shroud 12 has diametrically opposed slots which (FIG. 2) receive feet 32. Shoulders 32a bear against the inner surface of shroud 12. Coil spring 16 is compressed between bottom 36 of the claw unit and the dished top portion 12a of the shroud. The parts are assembled initially by dropping a claw unit onto body 10, depositing a coil spring 16 into the cup portion 34, 36 of the claw unit, and then forcing shroud l2 downward into place. During this latter operation, posts 28 are received in gaps 39 between the groups of claws 3.8. The posts are deflected resiliently inward, and when the shroud has been pushed into its final position, feet 32 snap into the slots of the shroud, thereby securing the four parts into a unitary fastener. Coil spring 16 is centered in dished end 12a of the shroud.

Compression coil spring 16 biases claw unit 14 downward as viewed in FIG. 2. When hooked portions 40 engage feet 32 of body 10, bottom 36 of the claw unit projects slightly below surface 20 of the body as viewed in FIG. 2. When the fastener is used to clamp panels A and B together, the claw unit is biased downward by the coil spring and claws 38 are projected outward to a greater diameter than that of wall portion 24 of the body so that the abutment ends of claws 38 are thrust against the exposed surface of panel A, securing panels A and B together.

When the fastener of FIGS. 1-6 is to be inserted into roughly aligned holes in panels A and B, and when the fastener is to be removed, claw unit 14 is driven upward toward top portion 12a of shroud 12. When in that configuration, all of the claws 38a become retracted inside the lateral wall 12b of the shroud, optionally leaving a tip of each claw 38 projecting below the rim 12c of the shroud. Rim 12c is of approximately the same diameter as cylindrical wall portion 24 adjacent flange l8, and the retracted claws collectively have a diameter that is preferably less than the diameter of wall portion 24 and in any case less than the diameter of the holes in the panels. Consequently, it is a simple matter to remove the fastener as a unit from the holes in panels A and B, and it is equally simple to insert the fastener through holes in the panel. When inserted, and when the claw unit is released for downward motion due to the bias of compression spring 16, claws 38 are guided along arcuate guide surfaces 26 until the cut ends of claws 38 abut and press firmly against the top surface of panel A, pulling flange I8 firmly against the chamfered or countersunk hole in panel B. In this configuration, the fastener securely holds panels A and B together. A certain amount of clearance is deliberately provided between the inner bore a of the body and the lateral wall 34 of the claw unit. Consequently, the claw unit is free to rock a little for assurance that claws 38 will be driven against panel A everywhere or nearly everywhere.

In a practical example of a fastener made in the form shown in FIGS. l-6, cylindrical wall portion 24 was one-half inch in diameter and compression coil spring 16 exerted a force of about pounds against bottom 36 of the claw unit in the configuration shown in FIG. 2. However, because of the outward slope of the ends of claws 38, diverging from each other at opposite sides of the fastener (note especially FIG. I), a separation force of about forty pounds was applied between panels A and B before those panels started to separate from each other (FIG. 6). Without providing embossed parts 38b on the claws, further separation between the panels required seventy pounds, and even ninety pounds was sustained successfully. This may be due to the divergent slopes of the end portions of claws 38 (about 30 in this example), which tend to spread outward as panel A is lifted away from panel B in FIG. 2. However, the ends of the sheet-metal claws have sharp cut edges which tend to dig into panel A and resist the force tending to spread them. In the test example, claws 38 were made of annealed stainless steel 0.010 inch thick. In any case, the force of spring 12 in resisting separation between the panels is greatly augmented. Rim of the shroud has only a bare minimum of clearance from the claws, so that the shroud tends to resist outward spreading of the claws at a very short distance from the ends of the claws. This action provides great stiffness and strength for the short lengths of the claws that project outside the shroud.

As an optional feature of special advantage, each of the claws 38 has an outward embossed projection 38b whose upper edge is lanced from the remainder of the claw. If a large spreading force were applied between panels A and B, those panels could separate somewhat as shown in FIG. 6. In so doing, the applied force would force claw unit 14 to shift upward and the claws 38 would be pushed part way into shroud 112. However, embossed portions 381; of the claws would engage rim 120 of the shroud, providing a positive interlock between panel A and shroud 12 which blocks any further separation between the panels, short of enormous destructive force that might be imposed on the short end portions of the claws 38 with their embossed portions 38b.

As seen in FIG. 3, the bottom of the fastener presents virtually a flat face at the exterior (bottom) of panel B. Surface 20 of body 10 is flush with bottom 36 of the claw unit; and as previously indicated, surface 20 is flush with the external surface of panel B. There is a narrow groove 42 surrounding bottom 36 of the claw unit, but this is quite small and inconspicuous. In many cases where the fastener is used for holding panels together, this flush external surface of the fastener is an important asset, as for example where the fastener is exposed at the outside surface of an airplane engine cowling. Additionally, the flush form of fastener is extremely attractive for holding the front panel on a cabinet. The fastener is also useful for securing a panel B to a post C (FIG. 13) in which a cavity is formed to receive the portion of the fastener projecting behind the panel. A modest undercut or groove Ca provides a shoulder for positive engagement by claws 38. The cut edges at the ends of claws 38 could dig into the wall of the cavity, where the material of post C is suitably soft, rendering groove Ca superfluous for light loading.

The fastener is useful as a door latch, as shown in FIG. 14, the fastener of FIGS. l6 being modified slightly for that application. In the modified fastener, the cylindrical wall portion 24' has a groove 24a in which there is received a snap-ring 46. The snap-ring secures the fastener to the outer panel B in FIG. 14, which may be a door. A wall portion A against which door B closes has a slight recess formed therein for accommodating ring 46. As the door is being closed, claws 38 must be retracted. Claws 38 are projected when the door is closed, and then the door is securely latched shut. A special tool is needed to release the fastener so that it constitutes a unique form of latch that is operable only by authorized personnel who have the necessary handle or tool for effecting release of the fastener as is described below in detail. The externally bell-like tapered form of shroud 12 enables the device to be used as a door latch a mere two inches from the door hinge.

FIG. 15 shows use of the fastener in uniting two panels D and E, each panel having a right-angled portion D and E. Two fasteners are shown in place for holding the parts D and E securely in assembly with each other. The spring bias of the fasteners urges the panels into firm fit at the corner, providing a rigid structure. The holes through which the fasteners extend should be a little over-size, to allow for the described firm fit at the corner.

The fastener will accommodate a relatively wide latitude of panel thicknesses, and no special preparation of the panels is needed in the application of the fastener shown in FIG. 2 other than to form holes large enough to admit the fastener but not so grossly over-sized as to escape cooperation with the claws 38. Pierced holes with prominent burrs need not be deburred before the fastener is used.

FIG. 7 illustrates the fastener of- FIGS. 1-6 together with portions of a tool that cooperates with the fastener for insertion and removal of the fastener. As seen in FIG. 7, there is an outer tube 48 having a cylindrical portion 48a of a diameter small enough to enter groove 42 (FIGS. 2 and 3). A number of tiny steel balls 50 are movable radially in portion 48a, but slight overhangs at the outside surface and at the inside surface of portion 48a retain the balls captive yet allow some radial shift of the balls. An inner rod 52 is slidable in outer tube 48.

When the tool is in its configuration as shown in FIG. 7, it is inserted into groove 42, the extent of insertion being limited by the depth of the groove. Balls 50 are shifted radially inward as tool portion 48a enters groove 42. After insertion of tool part 48a, rod 52 is shifted upward relative to outside tube 48. The upper edge of rod 52 drives balls 50 radially outward. They are received in a continuous undercut groove 42a in body 10. Thereafter, further upward shift of rod 52 carries the rod into driving contact with bottom 36 of the claw unit in the fastener, retracting claws 38 and holding the fastener in condition for removal as a unit. The fastener is retained on the working end of the tool parts illustrated in FIG. 7.

FIG. 8 shows a modification of the tool parts in FIG. 7. Outer tube 48' has resilient legs 48a which enter groove 42. Bumps 50' formed on resilient legs 48a replace balls 50. Rod 52 acts as before to drive bumps 50' outward into undercut 42a, the upper end of rod 52' engaging a cam surface 54 of each resilient leg 48a as the rod 52' drives upward.

When the tool is fully inserted (either the tool of FIG. 7 or that of FIG. 8), it is mechanically united to the fastener and claws 38 are retracted. In that condition, the tool and the fastener become a unit enabling the fastener to be removed or inserted, as may be required. Retraction of rod 52 or 52' releases the tool for removal from the fastener and releases the fastener for gripping the part or parts to which the fastener is assembled. Notably, the fastener can be used in a blind hole, where there is no access to the rear of the panel or panel assembly. It is only necessary for the front of the panel to be accessible to insert the fastener, and to release and remove it, as may be required subsequently.

Details of the whole tool, which includes tool parts similar to those of FIGS. 7 and 8, are shown in FIGS. 9-12. Fixed handle 56 is secured by screws 57 to body 58. Outer tube 48b of the tool is an integral part of body 58. Movable handle 60 of the tool is connected to handle 56 by a pivot pin 62. A U-shaped leaf spring 64 has its opposite extremities bearing against handle 60 and against pin 66 in handle 56, respectively. Spring 64 is looped around pivot pin 62 and provides separating bias for handles 56 and 60.

As seen in FIGS. 10 and 11, handle 60 has a pair of arms 60a that are received in grooves 68a of a body 68 that is slidable within body 58 attached to arm 56. Body 68 has an integral projection 52a corresponding to rods 52 and 52' in FIGS. 7 and 8. However, in the form of tool shown in FIGS. 9 to 12, tool part 52a is not a rod but instead it is a hollow part corresponding to roughly threequarters of a cylinder. An end view of the modified tool parts 48b and 52a is shown in FIG. 18 and is explained below in connection with the form of connecting device in FIG. 16. However, the modified tool parts 48b and 52a interlock with and release a fastening device in the same way as tool parts 48 and 52 perform in FIG. 7.

When a fastener is to be manipulated by the tool of FIGS. 9-12, handles 56 and 60 are spread apart as shown in FIG. 9. The end of the tool 48b is inserted into groove 42 (FIG. 2) of the fastener and then the handles 56 and 60 are gradually squeezed toward each other. As this occurs, part 52a advances and thereby causes balls 50 to project radially outward into undercut or groove 42a of the fastener. At this moment, tool part 48b is locked securely to body 10 of the fastener. Further squeezing motion of handles 56 and 60 forces tool part 52a to advance against the bottom of the claw unit 14 and then to compress spring 16 and retract claws 38. When the claw unit has been driven far enough into the fastener for the ends of claws 38 to recede to approximately the diameter of body portion 24 (see FIG. 19), movable handle 60 has advanced until the end of slot 60d reaches pin 66, blocking further motion. For looking handles 56 and 60 in this position, pin 66 can be manually shifted along slots 56a and 602 (radially from pin 62), and during that motion pin 66 snaps over detent portion 64a of the spring 64. The fastener at this point is virtually united to the tool, and handles 56 and 60 of the tool can be firmly squeezed toward each other without risking damage to the fastener. The tool and the fastener then behave as a single unit and can be manipulated for inserting or removing a fastener. Return of pin 66 to slot 60a releases handles 56 and 60 and allows spring 64 to retract tool part 52a, thereby allowing balls 50 to recede and releasing tool part 480 from interlocked engagement with the undercut or groove 42a (FIG. 7).

Reviewing the function of the tool, it is seen that there is an initial motion in which the end of the tool is inserted into groove 42 of a fastener; thereafter the internal sliding part of the tool projects the balls 50 radially outward to become interlocked with the undercut of the fastener body, and further motion of the slide compresses the helical coil spring and drives the claw unit so that the claws are retracted within a safe diameter for enabling removal of the fastener from the hole into which it was fitted or for insertion into a hole that is to receive the fastener. Reverse operation of the tool releases the tool from the fastener and allows coil compression spring 16 to drive the claw assembly against the parts to be united by the fastener.

The movable handle 60 is shown at a 90 attitude relative to the axis of the tool parts 48b and 52a. By shifting to arm 60band the second screw hole in handle 56, handle 60 can be disposed at a starting angle of 45 to the tool axis. A third screw hole in handle 56 and a third pair of arms 60c make possible an initial attitude of handle 60 in approximate alignment with the axis of the tool parts 48b and 50a. These various tool configurations add measurably to the comfortable and effective use of the tool.

FIG. 16 shows a modification of the fastener of FIGS. 16, inclusive, serving as a cable connector. The cable can be a mechanical guy wire or it can be an electrical conductor. The connector illustrated in FIG. 16 is 'shown received in a receptacle G with claws 38 received in, and bearing against, an undercut shoulder Ga. The connector of FIG. 16 is precisely the same in construction as that of FIGS. 1-6, inclusive, with but the following deviation. The bottom 36a of the claw unit has a cylindrical extruded portion 36b that receives and is united as by solder to the end portion 70 of an insulated wire.

The connector of FIG. 16 is very effective as a cable anchor, when it is used for the end of a guy wire, because the pulling stress that might be imposed on the wire is transmitted by claw unit 14 to the ends of the claws. Coil spring 16 guards against any loosening of the connector in the receptacle G, and maintains firm contact pressure of the claw ends against the undercut Ga.

The connector is very effective as an electrical connector because wire 70 is connected directly to claw unit 14 and that claw unit forms a direct metal conduction path to the receptacle G which receives the connector. As an electrical connector, the compression coil spring 16 develops a relatively large amount of force for establishing excellent electrical connection between the projecting claws 38 and the part of recep tacle G that is engaged by those claws. It will be recalled that, in a device of this form where the body has only a one-half inch diameter (disregarding the flange), spring 16 has a -pound force.

The tool of FIGS. 9-12 inclusive with the ends of the active portion of the tool formed as shown in FIG. 18 is adapted to insert and remove a connector of the forms shown in FIG. 16. The tool is used in exactly the same manner as the tool parts described in connection with the fastening device of FIGS. I6, but in connection with the connector of FIG. 16, the lateral opening 48d in the outer tubular part and the opening 52d in the slidable tool part admits the centrally projecting wire initially as the tool is advanced. into position opposite the groove 42.

An electrical connector which is the same in most respects as that of FIG. 16 is shown in FIG. 20. Unlike the connecting devices of FIGS. 2 and 16, the connector of FIG. 20 has a lateral flange 180 having a flat shoulder. The connector of FIG. 20 can be used to join a test wire 72 to a foil conductor H bonded to one face of a printed circuit board J of insulation. In this application of the connector, an insulating bushing K prevents flange 18a from engaging metal foil strip L bonded to an exposed face of another printed circuit board M. In

this way, test wire 72 can be used as a secure probe for firm connection to the foil conductor H of one printed circuit board without making connection to the foil strip L of the other printed circuit board. If connection is to be made to foil strip L alone, to the exclusion of foil strip H, then bushing K can be removed from the position shown in FIG. 20, then inserted into the opposite side of panel I with its flange overlying the portions of foil strip H near the hole, and finally the connector can be inserted so that flange 18a is pressed firmly against foil conductor L. If it were desired to connect wire 72 to both strips H and L, insulating bushing K could be omitted. Finally, a fastening device precisely in the form shown in FIG. 2 can be used to interconnect foil elements H and L of the two printed circuit boards in FIG. 20, omitting wire 72 in that application of a connector. Such a device can perform both for mounting a component securely on a printed circuit board and to provide a secure but separable electrical connection from the component to the printed circuit board.

A still further application of the basic fastener structure of FIGS. l6 is shown in FIG. I7, where the connector serves as a pneumatic or hydraulic plug-in connection. The parts in FIG. 17 bear the same numbers as in FIGS. l6 except for those parts which are modified. Only the modified parts are described here.

Flange 18b has a groove on its underface which re ceives an O-ring seal 74, and body portion 10 has an internal groove 76 which receives another O-ring 78. Claws 38 are spring biased against the internal surface of a wall P of a pressure vessel (which may be a manifold, for example) thereby pulling flange 18b toward wall P and compressing O ring seal 74. The O-ring 78 forms a seal between body 10 and lateral cylindrical wall 34 of the claw unit. Accordingly, the connector or fastener or connecting device of FIG. 17 is secured to the wall P in a pressure-tight manner. Indeed, the device of FIG. 17 would behave as a shut-off plug if the bottom of the claw unit in that device were formed in the same manner as that of FIG. 2. However, in the illustrated form of device in FIG. 17, the claw unit I4 has a cylindrical extrusion 80 which is united by solder or otherwise to a length of tubing 82 which may form part of a valve, a guage, a tube or some other device that is connected by a pressure-tight connecting device to the wall P of the pressure vessel. The connecting device of FIG. I7 is easily and quickly inserted and removed, using the tool of FIGS. 942, with the connectorengaging tool parts formed as shown in FIG. I8.

FIG. 19 shows a still further adaptation of the connector of FIGS. l-6, modified for mounting a rod 84 on a stationary wall R. The parts in FIG. 19 are shown with the claw unit 14 retracted, spring 16 being compressed by tool parts 48b and 52a.

The shroud or cowl 12 of the connector in FIG. 19 has an extruded tubular portion 12d projecting from its upper end, and the bottom 14c of claw unit 14 has a hole cut therethrough for receiving a screw 86 threaded into rod 84. Screw 86 holds a short length of tubing 88 firmly against the inside wall of the bottom of claw unit 14 and grips the bottom of the claw unit against one end of rod 84. Tubular extrusion 12d pro vides lateral support for tube 88 which is made rigid with rod 84 by screw 86, thereby maintaining the rod 841 firmly erect on wall R when tool parts 48b, 52a release claw unit M to bear against the wall.

In general, the panels or walls need not be modified to cooperate effectively with the connecting devices described. However it may be expedient to do so, as by uniting body t0 the outer panel B in which case the panel in effect becomes the flange. It may be desirable to adhere a washer of hard metal to the back of panel A in case panel A is of a soft material that is inadequate to provide the desired bearing or vibrational wear resistance for claws 38, or in case the panels are too thin for effective grip by the connecting device.

It has been indicated above that the basic form of the connecting devices is such that its parts can be made of metal. All-metal connecting devices described above are resistant to solvents, lubricants, and decomposition with age, and can be used where relatively high temperatures are encountered. All the parts are made of stainless steel for connecting devices that are exposed to corrosive atmospheres. Where electrical connections are to be made, the parts can be electroplated as with silver or gold for low contact resistance; and claw unit 14 is to be of a high-conductivity material for the connectors of FIGS. 16 and 20 (e.g., phosphor bronze) where large currents are to be carried.

The various connecting devices are notable for their ease of operation, yet high gripping strength. The tool handles develop force multiplication to compress even a heavily pre-biased spring. Especially when locked by pin 66, the tool of FIGS. 9-12 and 18 becomes a separable handle. For example, when a connecting device is used as a door or panel latch, the manipulating de vice of FIGS. 9-12 becomes a separable handle, serving as a part of the connecting device when interlocked therewith, yet being removable to prevent unauthorized access for protection of hazardous contents of a cabinet, and to guard against tampering and vandalism. Such a separable handle imparts a proprietary character to the connecting device. The circular groove 42 can be blocked at points, for further restricting or specializing the form of manipulating parts that can enter.

In practice, the various holes for the connecting devices are round, moderately larger than the body diameter 24. However, in suitable applications the openings can be slots allowing for insertion of a connecting device along a direction parallel to the plane of a panel.

In each connecting device shown, the claw unit has a lateral wall 34 that accommodates much of spring 16, the bottom 36 (perforate or imperforate) serving as a bearing surface for one end of the spring. The lateral wall 34 can be omitted and bearing surface 36 can be located at the level of claw portions 38a, provided that shroud I2 is made correspondingly deeper to provide space for spring 16, but such a construction would have the disadvantages of increasing the axial length of the device, and of leaving a dirt-accummulating unsightly cavity in body 10. Such a cavity is needed to allow a tool to engage the claw unit. In the illustrated forms of construction, it is a distinct advantage to include the cup 34-36 to reduce the axial dimension of the connecting devices. As a matter of terminology, wall 34 and bottom 36 is called a cup; and wall 34 and bottom 36a which has an opening therein is also called a cup, the bottom acting in both cases as a seat for spring 16 and as a thrust-applying point for the tool or handle part 52 or 52a. I

The claws 38 move divergently toward flange 18 to grip the mounting structure, it being necessary to move both toward the flange for gripping action and to have a radial outward component to become larger in diameter than portion 24 of body 10. In the example given, the ends of the claws slope 30 to the axis. This is a practical value of the slope. It is important for the thrust of the claws to develop a force needed to grip the mounting structure between the claws and the flange. The slope can be steeper, but then the tolerance of the hole in panel B would become tighter; and if the slope angle were made much flatter (e.g., 45) there would be some danger of the claw ends bending or sliding outward on panel A (FIG. 2) in case stress is developed tending to drive the claw back into the shroud. Obviously a latitude in the slope angle is permissible. so long as endwise thrust is the controlling stress in the claws.

A latitude of variationin the described embodiments is readily possible within the skill of the art, these embodiments being the forms of connecting devices presently preferred and which demonstrate an exemplary manner of applying the various novel features of the in vention. Further, the described connecting devices can readily be adapted to still further applications. Therefore the invention should be construed broadly in accordance with its full spirit and scope.

What is claimed is:

l. A connecting device, including i. a body having an outward-extending flange and a portion extending rearward of said flange and being receivable in a hole in apparatus to which the connecting device is to be secured with the flange pressed against a bearing surface adjacent to said hole in said apparatus;

ii. a claw unit including multiple elongated claws movable forward and rearward along said rearward extending portion of said body, said elongated claws having abutment ends movable generally forward and slightly outward into positions opposite said flange for engaging an abutment surface of said apparatus adjacent to the hole therein and said abutment ends being movable reversely into retracted positions, said elongated claws extending generally rearward and slightly inward from said abutment ends thereof, whereby said elongated claws are in lengthwise compression when said abutment ends bear against such abutment surface;

iii. a shroud secured to said body so that said shroud and said body form a body unit, said shroud having a rim for restricting outward movement of said elongated claws both in retracted and projected positions thereof; and

iv. spring means acting on said claw unit and reacting on said body unit for biasing said flange and said abutment ends of said claws generally toward each other for gripping the apparatus adjacent to the hole therein.

2. A connecting device in accordance with claim 1, wherein said body and said shroud are generally figures of revolution having a common axis, said shroud and a lateral surface of said body defining a space therebetween for providing lateral constraint for of said claws, and said abutment ends being distributed about said body.

3. A connecting device in accordance with claim 1, wherein said claws are curved along their length approximately as circular arcs, and wherein a lateral surface of said body provides a corresponding arcuate guide surface cooperable with intermediate portions of each of said claws for ensuring movement of the abutment ends of said claws forward and outward of said body.

4. A connecting device in accordance with claim 2, wherein said claws are curved along their length approximately as circular arcs, and wherein said lateral surface of said body provides a corresponding arcuate guide surface cooperable with intermediate portions of each of said claws for ensuring movement of the abutment ends of said claws forward and outward of said body, wherein said arcs are tangent to a line approximately parallel to the axis of said body at points remote from said flange, and said arcs of said claws having an extent of approximately 30.

5. A connecting device in accordance with claim 1, wherein said body includes at least one post to which said shroud is secured.

6. A connecting device in accordance with claim 2, wherein said claw unit includes a cup portion axially reciprocable in said body, and wherein said spring means is under compression and is confined endwise between said shroud and said cup.

7. A connecting device in accordance with claim 2, wherein said body has an outward-facing lateral guide surface for said claws sloping outward toward said flange, and a portion smaller in diameter than said flange between said flange and said lateral guide surface for penetrating a hole in the apparatus to which the connecting device is to be secured, the abutment ends of said claws projecting outward of said smaller diameter portion of said body for engaging a surface of the apparatus adjacent the hole in the apparatus, said claw unit being retractable to withdraw said abutment ends of said claws to a circle of reduced diameter for entry and removal from the hole in the apparatus.

8. A connecting device in accordance with claim 1, wherein said claws have outward projecting shoulders on portions thereof disposed outside said shroud when the abutment ends bear against the apparatus, said elongated claws being retractable slantwise for releasing the connecting device, said shoulders engaging said rim to be arrested thereby when separating force tending to separate apparatus parts gripped by the connecting device is imposed against said flange and the abutment ends of said claws.

9. A connecting device in accordance with claim 1, wherein said shroud and said claw unithave openings spaced apart along said axis for providing a passage through said connecting device.

10. A connecting device in accordance with claim 6, including a sealing ring opposite said flange and a sealing ring between said body and said cup portion of the claw unit for adapting said connecting device to form a fluid-tight assembly in said opening.

11. A connecting device in accordance with claim 10, wherein said cup portion has a tube united to and extending through the bottom thereof for providing a fluid passage through a wall in said apparatus in which the connecting device is secured.

12. A connecting device in accordance with claim 1, including a wire secured to said claw unit and projecting externally therefrom when said connecting device is secured in a receiving hole, said claw unit forming a continuous current path from the apparatus engaged by the abutment ends of said claws to said wire.

13. A connecting device in accordance with claim 9, including rod means extending through said openings, secured to at least one of said shroud and said claw unit and confined laterally by both of said shroud and said claw unit for stabilizing said rod means against tilting.

14. A connecting device in accordance with claim 1, including a guy wire secured to said claw unit and projecting externally therefrom when the connecting device is secured in a receiving hole, any tension applied to said guy wire being resisted by said claw unit alone.

15. A connecting device in accordance with claim 1, further including means for retaining said body assembled to a door or panel for retentive reception in a hole in a structure to which the door or panel is to be releasably latched.

16. A connecting device in accordance with claim 1, wherein said flange is tapered for engagement with a complementary tapered reliefin the exposed surface of a panel about a hole in which the connecting device is to be received, and wherein said claw unit includes a cup interconnecting said elongated claws and having a bottom substantially coplanar with the exposed surface of the flange when the connecting device is mounted on apparatus of prescribed thickness comprising said panel, so that the connecting device when mounted on said apparatus is flush with the surrounding surface of a panel in which it is received.

17. A connecting device in accordance with claim 1, wherein said body has a forward-opening recess in which a manipulating tool may be inserted, the body being formed with an undercut extending the recess laterally in which undercut a part of the tool may be interlocked, and the claw unit having a portion disposed in said recess but being smaller than the recess for providing a tool-admitting passage, said portion of the claw unit being externally accessible for engagement by another part of the tool for enforcing retraction of said claws to enable removal or insertion of the connecting device.

18. A connecting device in accordance with claim 6, wherein said body has a circular recess around said cup and a circular undercut encircling the cup and defining a shoulder, in which recess and undercut a tool part is receivable for interlocking with the body and said cup being accessible for engagement by another tool part for releasing manipulation.

19. A connecting device in accordance with claim 2, wherein said body has an axial bore therein, and wherein said claw unit includes a coaxial cylindrical portion in said bore, the elongated claws extending forward integrally from the rear end of said cylindrical portion, said cylindrical portion having an inward pro jecting portion at the forward end thereof, and wherein said biasing means is a compression coil spring coaxially within said cylindrical portion and confined endwise between said shroud and said inward projecting portion of said cylindrical portion.

20. A connecting device in accordance with claim 6, wherein said cup has an exposed bottom substantially flush with the forward surface of said flange in the installed condition of the apparatus.

21. A connecting device in accordance with claim 1, wherein said claws are of resilient sheet metal whose said abutting ends are directed toward the flange and have sharp cut edges.

22. A connecting device in accordance with claim 6, wherein said connecting device further has an annular externally exposed groove adjacent said cup and wherein said body has an undercut that opens into said groove.

23. A connecting device in accordance with claim 7, wherein said rim is disposed to engage and restrain respective intermediate portions of said elongated claws against radially outward motion when said claw unit is in its projected apparatus-gripping position.

24. A connecting device in accordance with claim 19, wherein said body is radially separated from said cylindrical portion by an externally exposed groove in which a manipulating device is receivable, said body having an undercut that opens into said groove, said connecting device having a separable manipulating device secured thereto including an outer member received in said groove and said outer member bearing at least one part movable radially outward and received in said undercut, said manipulating device having an inner part reciprocable along said axis and cooperable with said one part during a first part of a reciprocating stroke for driving said radially movable part into locked engagement with said undercut and said reciprocable part being engageable with said cylindrical portion during continuation of said reciprocating stroke for driving said claw unit into its retracted position against the bias of said spring means to condition said connecting device for release from or for assembly to apparatus having a hole for receiving the device.

25. A device for manipulating a connecting device as set forth in claim 22, including an outer member separably receivable in the groove in the connecting device and having at least one part movable radially outward and receivable in the undercut of the radially outward and receivable in the undercut of the connecting device in interlocked relationship therewith, and said manipulating device having an inner part axially operable for initially enforcing interlocking engagement of said radially movable part with said undercut and said inner part being operable farther for driving said claw unit against the bias of said spring means, to retract the claws of said claw unit, said outer and inner parts having aligned lateral recesses for clearing an external axially projecting portion of the connecting device.

26. In combination, a first device and a second device adapted to be separably united, said first device having a body, claw means reciprocable forward and rearward relative to said body into projected and retracted posi tions, respectively, and means for biasing said reciprocable claw means forward into said projected position, said first device being receivable in retentive assembly to apparatus when the claw means is in its retracted position, said body and said claw means being separated from each other by a forward-opening recess and said body having an undercut forming an inner shoulder adjoining said recess, said recess thereby affording access to said shoulder, said second device including a manipulating portion and first and second operating parts, said first part being receivable in said recess and having a lateral projection for retentive cooperation with said shoulder, said second part being cooperable with said first part to enforce retentive cooperation of said first part with said shoulder, said second part being further operable to engage and drive said claw means against the action of the biasing means into the retracted position thereof.

27. A connecting device including a body structure having an outward-extending flange and a portion extending rearward of said flange, said body structure being receivable in a hole in apparatus to which the connecting device is to be secured with the flange pressed against a bearing surface adjacent to said hole in the apparatus, a claw unit having portions engageable with an abutment surface of the apparatus, said body structure having an external opening encircled by said flange, said claw unit comprising a cup portion in said opening and having a bottom essentially flush with said flange, said opening being sufficiently larger than said cup bottom to provide a tool-receiving passage, and said body structure having an undercut adjacent said cup bottom extending laterally of said passage for interlocking reception with an inserted tool part, a spring acting between said claw unit and said body structure for biasing said flange against said apparatus and for biasing said cup in the opposite direction and for biasing said claw unit into its apparatus-engaging configuration, whereby the connecting device has a tamper-resistant relatively flat exterior adapted for cooperation with a specialized releasing tool. 

1. A connecting device, including i. a body having an outward-extending flange and a portion extending rearward of said flange and being receivable in a hole in apparatus to which the connecting device is to be secured with the flange pressed against a bearing surface adjacent to said hole in said apparatus; ii. a claw unit including multiple elongated claws movable forward and rearward along said rearward extending portion of said body, said elongated claws having abutment ends movable generally forward and slightly outward into positions opposite said flange for engaging an abutment surface of said apparatus adjacent to the hole therein and said abutment ends being movable reversely into retracted positions, said elongated claws extending generally rearward and slightly inward from said abutment ends thereof, whereby said elongated claws are in lengthwise compression when said abutment ends bear against such abutment surface; iii. a shroud secured to said body so that said shroud and said body form a body uniT, said shroud having a rim for restricting outward movement of said elongated claws both in retracted and projected positions thereof; and iv. spring means acting on said claw unit and reacting on said body unit for biasing said flange and said abutment ends of said claws generally toward each other for gripping the apparatus adjacent to the hole therein.
 2. A connecting device in accordance with claim 1, wherein said body and said shroud are generally figures of revolution having a common axis, said shroud and a lateral surface of said body defining a space therebetween for providing lateral constraint for of said claws, and said abutment ends being distributed about said body.
 3. A connecting device in accordance with claim 1, wherein said claws are curved along their length approximately as circular arcs, and wherein a lateral surface of said body provides a corresponding arcuate guide surface cooperable with intermediate portions of each of said claws for ensuring movement of the abutment ends of said claws forward and outward of said body.
 4. A connecting device in accordance with claim 2, wherein said claws are curved along their length approximately as circular arcs, and wherein said lateral surface of said body provides a corresponding arcuate guide surface cooperable with intermediate portions of each of said claws for ensuring movement of the abutment ends of said claws forward and outward of said body, wherein said arcs are tangent to a line approximately parallel to the axis of said body at points remote from said flange, and said arcs of said claws having an extent of approximately 30*.
 5. A connecting device in accordance with claim 1, wherein said body includes at least one post to which said shroud is secured.
 6. A connecting device in accordance with claim 2, wherein said claw unit includes a cup portion axially reciprocable in said body, and wherein said spring means is under compression and is confined endwise between said shroud and said cup.
 7. A connecting device in accordance with claim 2, wherein said body has an outward-facing lateral guide surface for said claws sloping outward toward said flange, and a portion smaller in diameter than said flange between said flange and said lateral guide surface for penetrating a hole in the apparatus to which the connecting device is to be secured, the abutment ends of said claws projecting outward of said smaller diameter portion of said body for engaging a surface of the apparatus adjacent the hole in the apparatus, said claw unit being retractable to withdraw said abutment ends of said claws to a circle of reduced diameter for entry and removal from the hole in the apparatus.
 8. A connecting device in accordance with claim 1, wherein said claws have outward projecting shoulders on portions thereof disposed outside said shroud when the abutment ends bear against the apparatus, said elongated claws being retractable slantwise for releasing the connecting device, said shoulders engaging said rim to be arrested thereby when separating force tending to separate apparatus parts gripped by the connecting device is imposed against said flange and the abutment ends of said claws.
 9. A connecting device in accordance with claim 1, wherein said shroud and said claw unit have openings spaced apart along said axis for providing a passage through said connecting device.
 10. A connecting device in accordance with claim 6, including a sealing ring opposite said flange and a sealing ring between said body and said cup portion of the claw unit for adapting said connecting device to form a fluid-tight assembly in said opening.
 11. A connecting device in accordance with claim 10, wherein said cup portion has a tube united to and extending through the bottom thereof for providing a fluid passage through a wall in said apparatus in which the connecting device is secured.
 12. A connecting device in accordance with claim 1, including a wire secured to said claw unit and projecting eXternally therefrom when said connecting device is secured in a receiving hole, said claw unit forming a continuous current path from the apparatus engaged by the abutment ends of said claws to said wire.
 13. A connecting device in accordance with claim 9, including rod means extending through said openings, secured to at least one of said shroud and said claw unit and confined laterally by both of said shroud and said claw unit for stabilizing said rod means against tilting.
 14. A connecting device in accordance with claim 1, including a guy wire secured to said claw unit and projecting externally therefrom when the connecting device is secured in a receiving hole, any tension applied to said guy wire being resisted by said claw unit alone.
 15. A connecting device in accordance with claim 1, further including means for retaining said body assembled to a door or panel for retentive reception in a hole in a structure to which the door or panel is to be releasably latched.
 16. A connecting device in accordance with claim 1, wherein said flange is tapered for engagement with a complementary tapered relief in the exposed surface of a panel about a hole in which the connecting device is to be received, and wherein said claw unit includes a cup interconnecting said elongated claws and having a bottom substantially coplanar with the exposed surface of the flange when the connecting device is mounted on apparatus of prescribed thickness comprising said panel, so that the connecting device when mounted on said apparatus is flush with the surrounding surface of a panel in which it is received.
 17. A connecting device in accordance with claim 1, wherein said body has a forward-opening recess in which a manipulating tool may be inserted, the body being formed with an undercut extending the recess laterally in which undercut a part of the tool may be interlocked, and the claw unit having a portion disposed in said recess but being smaller than the recess for providing a tool-admitting passage, said portion of the claw unit being externally accessible for engagement by another part of the tool for enforcing retraction of said claws to enable removal or insertion of the connecting device.
 18. A connecting device in accordance with claim 6, wherein said body has a circular recess around said cup and a circular undercut encircling the cup and defining a shoulder, in which recess and undercut a tool part is receivable for interlocking with the body and said cup being accessible for engagement by another tool part for releasing manipulation.
 19. A connecting device in accordance with claim 2, wherein said body has an axial bore therein, and wherein said claw unit includes a coaxial cylindrical portion in said bore, the elongated claws extending forward integrally from the rear end of said cylindrical portion, said cylindrical portion having an inward projecting portion at the forward end thereof, and wherein said biasing means is a compression coil spring coaxially within said cylindrical portion and confined endwise between said shroud and said inward projecting portion of said cylindrical portion.
 20. A connecting device in accordance with claim 6, wherein said cup has an exposed bottom substantially flush with the forward surface of said flange in the installed condition of the apparatus.
 21. A connecting device in accordance with claim 1, wherein said claws are of resilient sheet metal whose said abutting ends are directed toward the flange and have sharp cut edges.
 22. A connecting device in accordance with claim 6, wherein said connecting device further has an annular externally exposed groove adjacent said cup and wherein said body has an undercut that opens into said groove.
 23. A connecting device in accordance with claim 7, wherein said rim is disposed to engage and restrain respective intermediate portions of said elongated claws against radially outward motion when said claw unit is in its projected apparatus-gripping position.
 24. A connecting dEvice in accordance with claim 19, wherein said body is radially separated from said cylindrical portion by an externally exposed groove in which a manipulating device is receivable, said body having an undercut that opens into said groove, said connecting device having a separable manipulating device secured thereto including an outer member received in said groove and said outer member bearing at least one part movable radially outward and received in said undercut, said manipulating device having an inner part reciprocable along said axis and cooperable with said one part during a first part of a reciprocating stroke for driving said radially movable part into locked engagement with said undercut and said reciprocable part being engageable with said cylindrical portion during continuation of said reciprocating stroke for driving said claw unit into its retracted position against the bias of said spring means to condition said connecting device for release from or for assembly to apparatus having a hole for receiving the device.
 25. A device for manipulating a connecting device as set forth in claim 22, including an outer member separably receivable in the groove in the connecting device and having at least one part movable radially outward and receivable in the undercut of the radially outward and receivable in the undercut of the connecting device in interlocked relationship therewith, and said manipulating device having an inner part axially operable for initially enforcing interlocking engagement of said radially movable part with said undercut and said inner part being operable farther for driving said claw unit against the bias of said spring means, to retract the claws of said claw unit, said outer and inner parts having aligned lateral recesses for clearing an external axially projecting portion of the connecting device.
 26. In combination, a first device and a second device adapted to be separably united, said first device having a body, claw means reciprocable forward and rearward relative to said body into projected and retracted positions, respectively, and means for biasing said reciprocable claw means forward into said projected position, said first device being receivable in retentive assembly to apparatus when the claw means is in its retracted position, said body and said claw means being separated from each other by a forward-opening recess and said body having an undercut forming an inner shoulder adjoining said recess, said recess thereby affording access to said shoulder, said second device including a manipulating portion and first and second operating parts, said first part being receivable in said recess and having a lateral projection for retentive cooperation with said shoulder, said second part being cooperable with said first part to enforce retentive cooperation of said first part with said shoulder, said second part being further operable to engage and drive said claw means against the action of the biasing means into the retracted position thereof.
 27. A connecting device including a body structure having an outward-extending flange and a portion extending rearward of said flange, said body structure being receivable in a hole in apparatus to which the connecting device is to be secured with the flange pressed against a bearing surface adjacent to said hole in the apparatus, a claw unit having portions engageable with an abutment surface of the apparatus, said body structure having an external opening encircled by said flange, said claw unit comprising a cup portion in said opening and having a bottom essentially flush with said flange, said opening being sufficiently larger than said cup bottom to provide a tool-receiving passage, and said body structure having an undercut adjacent said cup bottom extending laterally of said passage for interlocking reception with an inserted tool part, a spring acting between said claw unit and said body structure for biasing said flange against said apparatus and for biasing said cup in the opposiTe direction and for biasing said claw unit into its apparatus-engaging configuration, whereby the connecting device has a tamper-resistant relatively flat exterior adapted for cooperation with a specialized releasing tool. 